Fear puke?
The almost vomiting reaction when he realized there was no way for him to rationalize the identical misspelled handwritings freaked the shetz out of me.
An instantaneous intense overwhelming sensation of the bad.
Is that a researched thing? Getting so afraid you want to puke? He even mentioned it in the bathroom "and the coughing...". I know about people puking from nerves and that seemed like just that.